Display device

ABSTRACT

A display device includes a display module including a first non-folding area, a second non-folding area, and a folding area disposed between the first and second non-folding areas which are arranged in a first direction, a first support disposed below the first non-folding area, a second support disposed below the second non-folding area, and a hinge including a biaxial rotation shaft disposed between the first support and the second support, the biaxial rotation shaft extending in a second direction intersecting the first direction. The folding area has a curvature radius in a range of about 1.5 mm to about 5.0 mm when the display module is folded by a rotation of the first support and the second support with respect to the biaxial rotation shaft.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority to and benefits of Korean PatentApplication No. 10-2020-0078744 under 35 U.S.C. § 119, filed on Jun. 26,2020 in the Korean Intellectual Property Office, the entire contents ofwhich are incorporated herein by reference.

BACKGROUND (a) Technical Field

The disclosure herein relates to a display device.

(b) Description of the Related Art

An electronic device for providing an image to a user, for example, asmartphone, a digital camera, a laptop computer, a navigation unit, anda smart television, may include a display device for displaying animage. The display device generates an image to provide the generatedimage to the user through a display screen.

In recent years, as technologies of the display device are developed,various types of display devices have been developed. For example,various flexible display devices that are deformable, foldable, androllable into a curved shape have been developed. The flexible displaydevices that are deformable into various shapes may be portable and thusincrease user convenience.

A folding display device among the flexible display devices may includea display module folded with respect to a folding axis extending in onedirection. The display module may be folded or unfolded with respect tothe folding axis. The display module may include a folding area that maybe bent during a folding operation. As the folding area is repeatedlyfolded or unfolded, the folding area may be deformed. Thus, a technologycapable of reducing deformation of the folding area is currently indemand.

It is to be understood that this background of the technology sectionis, in part, intended to provide useful background for understanding thetechnology. However, this background of the technology section may alsoinclude ideas, concepts, or recognitions that were not part of what wasknown or appreciated by those skilled in the pertinent art prior to acorresponding effective filing date of the subject matter disclosedherein.

SUMMARY

The disclosure provides a display device capable of reducing deformationof a folding area.

An embodiment provides a display device that may include a displaymodule including a first non-folding area, a second non-folding area,and a folding area disposed between the first non-folding area and thesecond non-folding area, the first non-folding area, the secondnon-folding area, and the folding area being arranged in a firstdirection; a first support disposed below the first non-folding area; asecond support disposed below the second non-folding area; and a hingeincluding a biaxial rotation shaft disposed between the first supportand the second support, the biaxial rotation shaft extending in a seconddirection intersecting the first direction. The folding area may have acurvature radius in a range of about 1.5 mm to about 5.0 mm when thedisplay module is folded by a rotation of the first support and thesecond support with respect to the biaxial rotation shaft.

In an embodiment, the folding area may have a length in a range of about35 mm to about 45 mm in the first direction when the display module isunfolded.

In an embodiment, the folding area may include a curved part bent tohave the curvature radius when the display module is folded; a firstextension part bent from the first non-folding area to extend to thecurved part; and a second extension part bent from the secondnon-folding area to extend to the curved part, wherein a distancebetween the first non-folding area and the second non-folding area maybe less than the curvature radius of the curved part of the folding areawhen the display module is folded.

In an embodiment, the first extension part and the second extension partmay be symmetric when the display module is folded, and the firstextension part may form an acute angle with a first reference lineextending from the first non-folding area to the curved part in a samedirection as an extension direction of the first non-folding area whenthe display module is folded.

In an embodiment, the acute angle may be in a range of about 6.5° toabout 12.5°.

In an embodiment, the display device may further include a first supportplate disposed between the first support and the first non-folding area;and a second support plate disposed between the second support and thesecond non-folding area, wherein the first support plate may extendbelow the first extension part and the curved part, the second supportplate may extend below the second extension part and the curved part,and the first support plate may be spaced apart from the second supportplate below the curved part.

In an embodiment, the first support plate and the second support platemay be attached to the first non-folding area, the second non-foldingarea, the first extension part, and the second extension part, and thefirst support plate and the second support plate may not be attached tothe curved part.

In an embodiment, the first support plate may be bent at a boundarybetween the first non-folding area and the first extension part when thedisplay module is folded, and the second support plate may be bent at aboundary between the second non-folding area and the second extensionpart when the display module is folded.

In an embodiment, each of the first support plate and the second supportplate may have a thickness in a range of about 80 μm to about 150 μm ina third direction perpendicular to a plane defined by the first andsecond directions when the display module is unfolded.

In an embodiment, the display device may further include a black coatinglayer coated on each of a top surface of the first support plate and atop surface of the second support plate; a first cushion layer disposedbelow the first support plate; and a second cushion layer disposed belowthe second support plate.

In an embodiment, the first support may extend below the first extensionpart, the second support may extend below the second extension part, atop surface of the first support facing the first extension part mayhave a first inclined surface in a plan view, and a top surface of thesecond support facing the second extension part may have a secondinclined surface in the plan view.

In an embodiment, the display device may further include a first wingplate disposed between the first extension part and the first inclinedsurface of the top surface of the first support and rotatably connectedto a portion of the first support, wherein the portion of the firstsupport may overlap a boundary between the first non-folding area andthe first extension part in a plan view; and a second wing platedisposed between the second extension part and the second inclinedsurface of the top surface of the second support and rotatably connectedto a portion of the second support, wherein the portion of the secondsupport may overlap a boundary between the second non-folding area andthe second extension part in a plan view, wherein the first wing plateand the second wing plate may rotate with respect to a first rotationshaft and a second rotation shaft extending in the second direction.

In an embodiment, the second wing plate may be symmetric to the firstwing plate, the second inclined surface of the top surface of the secondsupport may be symmetric to the first inclined surface of the topsurface of the first support, a distance between the first wing plateand the first inclined surface of the top surface of the first supportmay increase in a direction toward the curved part when the displaymodule is unfolded, and the first inclined surface of the top surface ofthe first support may form an angle in a range of about 6.5° to about12.5° with the first wing plate when the display module is unfolded.

In an embodiment, the first wing plate may contact the first inclinedsurface of the top surface of the first support, and the second wingplate may contact the second inclined surface of the top surface of thesecond support upon a stress of the folding area when the display moduleis folded.

In an embodiment, the hinge may include a cover part disposed betweenthe first support and the second support and below the first wing plateand the second wing plate; a first rotation unit and a second rotationunit connected to opposite ends of the cover part in the seconddirection; and a plurality of hinge parts connected to opposite sides ofthe first support and the second support in the second direction, andthe first rotation unit and the second rotation unit, wherein the coverpart may include a groove facing the curved part and extending in thesecond direction, and the biaxial rotation shaft may overlap the curvedpart and the groove in a plan view.

In an embodiment, a side of the first wing plate and a side of thesecond wing plate facing each other, and a central portion of the curvedpart may be disposed in the groove when the display module is folded.

In an embodiment, the first non-folding area may face the secondnon-folding area when the display module is in-folded.

In an embodiment, a display device may include a display panel includinga first non-folding area, a second non-folding area, and a folding areadisposed between the first non-folding area and the second non-foldingarea, the first non-folding area, the second non-folding area, and thefolding area being arranged in a first direction; a reflectionpreventing layer disposed on the display panel; a window disposed on thereflection preventing layer; a window protection layer disposed on thewindow; a panel protection layer disposed below the display panel; afirst support plate disposed below the first non-folding area; and asecond support plate disposed below the second non-folding area. Thefolding area may include a curved part having a predetermined curvatureradius when the display panel is folded; a first extension part bentfrom the first non-folding area extending to the curved part; and asecond extension part bent from the second non-folding area extending tothe curved part. A distance between the first non-folding area and thesecond non-folding area may be less than the predetermined curvatureradius of the curved part when the display panel is folded.

In an embodiment, the window may have a thickness greater than about 30μm and equal to or less than about 80 μm, the window protection layermay have a thickness in a range of about 55 μm to about 100 μm, and eachof the first support plate and the second support plate may have athickness in a range of about 80 μm to about 150 μm in a third directionperpendicular to a plane defined by the first direction and the seconddirection.

In an embodiment, the display device may further include a black coatinglayer coated on each of a top surface of the first support plate and atop surface of the second support plate; a first adhesive layer disposedbetween the window protection layer and the window; a second adhesivelayer disposed between the window and the reflection preventing layer; athird adhesive layer disposed between the display panel and the panelprotection layer; and a fourth adhesive layer disposed between the panelprotection layer and the black coating layer.

In an embodiment, a display device may include a display moduleincluding a first non-folding area, a second non-folding area, and afolding area disposed between the first non-folding area and the secondnon-folding area, the first non-folding area, the second non-foldingarea, and the folding area being arranged in a first direction; a firstsupport disposed below the first non-folding area; and a second supportdisposed below the second non-folding area. The display module may befolded by rotation of the first support and the second support thatrotate with respect to biaxial rotation shafts disposed below thefolding area. The folding area may include a curved part bent to have apredetermined curvature radius when the display panel is folded; a firstextension part disposed between the first non-folding area and thecurved part; and a second extension part disposed between the secondnon-folding area and the curved part. The folding area may have a lengthin a range of about 35 mm to about 45 mm in the first direction when thedisplay panel is unfolded, and the first extension part may form anangle in a range of about 6.5° to about 12.5° with a first referenceline extending from the first non-folding area to the curved part in asame direction as an extension direction of the non-folding area whenthe display module is folded.

In an embodiment, the curved part of the folding area may be bent tohave a predetermined curvature radius in a range of about 1.5 mm toabout 5.0 mm.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure, and are incorporated in and constitutea part of this specification. The drawings illustrate embodiments and,together with the description, serve to explain principles of thedisclosure. In the drawings:

FIG. 1 is a perspective view illustrating a display device according toan embodiment;

FIG. 2 is a view illustrating a folded state of the display device inFIG. 1 ;

FIG. 3 is a perspective view illustrating a display device according toan embodiment;

FIG. 4 is a view illustrating a folded state of the display device inFIG. 3 ;

FIG. 5 is a plan view illustrating the display device in FIG. 1 ;

FIG. 6 is a schematic cross-sectional view taken along line I-I′ of FIG.1 ;

FIG. 7 is a schematic cross-sectional view exemplarily illustrating adisplay panel in FIG. 6 ;

FIGS. 8 to 10 are views illustrating various bent states of the displaymodule and support plates;

FIGS. 11 and 12 are exploded perspective views illustrating a support onwhich the display module and the support plate in FIG. 6 are disposed;

FIG. 13 is a plan view illustrating the support obtained by couplingfirst and second supports, first and second wing plates, and a hinge inFIGS. 11 and 12 ;

FIG. 14 is a perspective view illustrating the support in FIG. 13 ;

FIG. 15 is a view illustrating a folded state of the support in FIG. 14;

FIG. 16 is a schematic cross-sectional view taken along line II-II′ ofFIG. 14 ;

FIG. 17 is a view illustrating a folded state of the display device inFIG. 16 ;

FIG. 18 is an enlarged photograph illustrating a folding area of acomparative display module;

FIG. 19 is a graph showing a deformed state of the folding area in FIG.18 ;

FIG. 20 is an enlarged photograph showing the folding area of thedisplay module according to an embodiment;

FIG. 21 is a graph showing a deformed state of the folding area in FIG.20 ;

FIG. 22 is an enlarged photograph showing a surface of the comparativedisplay module; and

FIG. 23 is an enlarged photograph showing a surface of the displaymodule in FIG. 6 .

DETAILED DESCRIPTION OF THE EMBODIMENTS

In this specification, it will also be understood that when onecomponent (or region, layer, portion) is referred to as being ‘on’,‘connected to’, or ‘coupled to’ another component, it can be directlydisposed/connected/coupled on/to the one component, or an interveningthird component may also be present.

Like reference numerals refer to like elements throughout. Also, in thefigures, the thickness, ratio, and dimensions of components areexaggerated for clarity of illustration.

The term “and/or” includes any and all combinations of one or more ofthe associated listed items.

The terms “and” and “or” may be used in the conjunctive or disjunctivesense and may be understood to be equivalent to “and/or.” In thespecification and the claims, the phrase “at least one of” is intendedto include the meaning of “at least one selected from the group of” forthe purpose of its meaning and interpretation. For example, “at leastone of A and B” may be understood to mean “A, B, or A and B.

As used herein, the singular forms “a,” “an,” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise.

It will be understood that although the terms such as ‘first’ and‘second’ are used herein to describe various elements, these elementsshould not be limited by these terms. The terms are only used todistinguish one component from other components. For example, a firstelement referred to as a first element in one embodiment can be referredto as a second element in another embodiment without departing from thescope of the appended claims. The terms of a singular form may includeplural forms unless referred to the contrary.

The spatially relative terms “below”, “beneath”, “lower”, “above”,“upper”, or the like, may be used herein for ease of description todescribe the relations between one element or component and anotherelement or component as illustrated in the drawings. It will beunderstood that the spatially relative terms are intended to encompassdifferent orientations of the device in use or operation, in addition tothe orientation depicted in the drawings. For example, in the case wherea device illustrated in the drawing is turned over, the devicepositioned “below” or “beneath” another device may be placed “above”another device. Accordingly, the illustrative term “below” may includeboth the lower and upper positions. The device may also be oriented inother directions and thus the spatially relative terms may beinterpreted differently depending on the orientations.

Additionally, the terms “overlap” or “overlapped” mean that a firstobject may be above or below or to a side of a second object, and viceversa. Additionally, the term “overlap” may include layer, stack, faceor facing, extending over, covering or partly covering or any othersuitable term as would be appreciated and understood by those ofordinary skill in the art. The terms “face” and “facing” mean that afirst element may directly or indirectly oppose a second element. In acase in which a third element intervenes between the first and secondelement, the first and second element may be understood as beingindirectly opposed to one another, although still facing each other.When an element is described as ‘not overlapping’ or ‘to not overlap’another element, this may include that the elements are spaced apartfrom each other, offset from each other, or set aside from each other orany other suitable term as would be appreciated and understood by thoseof ordinary skill in the art.

The phrase “in a plan view” means viewing the object from the top, andthe phrase “in a schematic cross-sectional view” means viewing across-section of which the object is vertically cut from the side.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system). For example, “about” may mean within one or morestandard deviations, or within +30%, 20%, 10%, 5% of the stated value.

As used herein, the term “unit” and/or “module” denotes a structure orelement as illustrated in the drawings and as described in thespecification. However, the disclosure is not limited thereto. The term“unit” and/or “module” is not to be limited to that which is illustratedin the drawings.

Also, ““under”, “below”, “above”, “upper”, and the like are used forexplaining relation association of components illustrated in thedrawings. The terms may be a relative concept and described based ondirections expressed in the drawings but are not limited thereto.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as generally understood bythose skilled in the art. Terms as defined in a commonly used dictionaryshould be construed as having the same meaning as in an associatedtechnical context, and unless defined apparently in the description, theterms are not ideally or excessively construed as having a formalmeaning.

The meaning of ‘include’, ‘includes’, ‘including’ or ‘comprise’,‘comprises’, or ‘comprising’ or ‘has’, ‘have’ or ‘having’ and theirvariations specify a property, a fixed number, a step, an operation, anelement, a component or a combination thereof, but does not excludeother properties, fixed numbers, steps, operations, elements, componentsor combinations thereof.

Hereinafter, embodiments will be described in detail with reference tothe accompanying drawings.

FIG. 1 is a perspective view illustrating a display device according toan embodiment. FIG. 2 is a view illustrating a folded state of thedisplay device in FIG. 1 .

Referring to FIG. 1 , a display device DD according to an embodiment mayhave a substantially rectangular shape having long sides in a firstdirection DR1 and short sides in a second direction DR2 intersecting thefirst direction DR1. However, the embodiment is not limited thereto. Forexample, the display device DD may have various shapes such as asubstantially circular shape and a substantially polygonal shape. Thedisplay device DD may be a flexible display device.

Hereinafter, a direction that intersects a plane defined by the firstand second directions DR1 and DR2 in a substantially perpendicularmanner is defined as a third direction DR3. In the specification, anexpression “viewed on a plane” may be defined as a state when viewed inthe third direction DR3.

The display device DD may include a folding area FA and non-foldingareas NFA1 and NFA2. The non-folding areas NFA1 and NFA2 may include afirst non-folding area NFA1 and a second non-folding area NFA2. Thefolding area FA may be disposed between the first non-folding area NFA1and the second non-folding area NFA2. The folding area FA, the firstnon-folding area NFA1, and the second non-folding area NFA2 may bearranged in the first direction DR1.

Although a folding area FA and two non-folding areas NFA1 and NFA2 areillustrated, the embodiment is not limited to the number of each of thefolding area FA and the non-folding areas NFA1 and NFA2. For example,the display device DD may include two or more non-folding areas andfolding areas disposed therebetween.

A top surface of the display device DD may be defined as a displaysurface DS and have a plane defined by the first direction DR1 and thesecond direction DR2. Images IM generated in the display device DD maybe provided to a user through the display surface DS.

The display surface DS may include a display area DA and a non-displayarea NDA around the display area DA. The display area DA may display animage, and the non-display area NDA may display no image. Thenon-display area NDA may define an edge of the display device DD, whichmay surround or may be adjacent to the display area DA and may beprinted in a predetermined color.

Referring to FIG. 2 , the display device DD may be a folding-type(foldable) display device that may be folded or unfolded. For example,the display device DD may be folded such that the folding area FA isbent with respect to a folding axis FX parallel to the second directionDR2. The folding axis FX may be defined as a minor axis parallel to theshort side of the display device DD.

In a case that the display device DD is folded, the first non-foldingarea NFA1 and the second non-folding area NFA2 may face each other, andthe display device DD may be in-folded so that the display surface DS isnot exposed to the outside.

FIG. 3 is a perspective view illustrating a display device according toan embodiment. FIG. 4 is a view illustrating a folded state of thedisplay device in FIG. 3 .

A display device DD_1 in FIG. 3 may have substantially the sameconfiguration as the display device DD in FIG. 1 except for a foldingoperation. Thus, hereinafter, the folding operation of the displaydevice DD_1 will be mainly described.

Referring to FIGS. 3 and 4 , the display device DD_1 may include afolding area FA′ and non-folding areas NFA1′ and NFA2′. The non-foldingareas NFA1′ and NFA2′ may include a first non-folding area NFA1′ and asecond non-folding area NFA2′. The folding area FA′ may be disposedbetween the first non-folding area NFA1′ and the second non-folding areaNFA2′. The folding area FA′, the first non-folding area NFA1′, and thesecond non-folding area NFA2′ may be arranged in the second directionDR2.

The display device DD_1 may be folded such that the folding area FA′ isbent with respect to a folding axis FX′ parallel to the first directionDR1. The folding axis FX′ may be defined as a major axis parallel to along side of the display device DD_1. The display device DD in FIG. 1may be folded with respect to the minor axis, and, in contrast, thedisplay device DD_1 in FIG. 3 may be folded with respect to the majoraxis. The display device DD_1 may be in-folded so that the displaysurface DS is not exposed to the outside.

Hereinafter, the display device DD that is in-folded with respect to thefolding axis FX parallel to the minor axis will be described.

FIG. 5 is a plan view illustrating the display device DD in FIG. 1 .

Referring to FIG. 5 , the display device DD may include a display panelDP, a scan driver SDV, a data driver DDV, an emission driver EDV, andpads PD.

The display panel DP may have a substantially rectangular shape havinglong sides extending in the first direction DR1 and short sidesextending in the second direction DR2. However, the embodiment is notlimited to the shape of the display panel DP. The display panel DP mayinclude a display area DA and a non-display area NDA surrounding oradjacent to the display area DA.

The display panel DP may include pixels PX, scan lines SL1 to SLm, datalines DL1 to DLn, emission lines EL1 to ELm, first and second controllines CSL1 and CSL2, first and second power lines PL1 and PL2, andconnection lines CNL.

Here, m and n are integers.

The pixels PX may be disposed on the display area DA. The scan driverSDV and the emission driver EDV may be disposed on the non-display areasNDA adjacent to the long sides of the display panel DP, respectively.The data driver DDV may be disposed on the non-display area NDA adjacentto one of the short sides of the display panel DP. When viewed in a planview, the data driver DDV may be disposed adjacent to a lower end of thedisplay panel DP.

The scan lines SL1 to SLm may each extend in the second direction DR2and may be electrically connected to the pixels PX and the scan driverSDV. The data lines DL1 to DLn may each extend in the first directionDR1 and may be electrically connected to the pixels PX and the datadriver DDV. The emission lines EL1 to ELm may each extend in the seconddirection DR2 and may be electrically connected to the pixels PX and theemission driver EDV.

The first power line PL1 may extend in the first direction DR1 and maybe disposed on the non-display area NDA. Although the first power linePL1 may be disposed between the display area DA and the emission driverEDV, the embodiment is not limited thereto. For example, the first powerline PL1 may be disposed between the display area DA and the scan driverSDV.

The connection lines CNL may each extend in the second direction DR2 andmay be arranged in the first direction DR1. The connection lines CNL maybe electrically connected to the first power line PL1 and the pixels PX.A first voltage may be applied to the pixels PX through the first powerline PL1 and the connection lines CNL electrically connected to eachother.

The second power line PL2 may be disposed on the non-display area NDA.The second power line PL2 may extend along the long sides of the displaypanel DP, and the other of the short sides of the display panel DP atwhich the data driver DDV is not disposed. The second power line PL2 maybe disposed further than the scan driver SDV and the emission driverEDV.

Although not shown, the second power line PL2 may extend toward thedisplay area DA and may be electrically connected to the pixels PX. Asecond voltage having a level lower than the first voltage may beapplied to the pixels PX through the second power line PL2.

The first control line CSL1 may be electrically connected to the scandriver SDV and may extend toward the lower end of the display panel DPwhen viewed on the plane. The first control line CSL1 may beelectrically connected to the scan driver SDV and may extend toward thelower end of the display panel DP when viewed on the plane. The datadriver DDV may be disposed between the first control line CSL1 and thesecond control line CSL2.

The pads PD may be disposed on the display panel DP. The pads PD may bedisposed closer to the lower end of the display panel DP than to thedata driver DDV. The data driver DDV, the first power line PL1, thesecond power line PL2, the first control line CSL1, and the secondcontrol line CSL2 may be electrically connected to the pads PD. The datalines DL1 to DLn may be electrically connected to the data driver DDV,and the data driver DDV may be electrically connected to the pads PDcorresponding to the data lines DL1 to DLn.

Although not shown, the display device DD may include a timingcontroller for controlling an operation of each of the scan driver SDV,the data driver DDV, and the emission driver EDV and a voltage generatorfor generating the first and second voltages. The timing controller andthe voltage generator may be electrically connected to correspondingpads PD through a printed circuit board.

The scan driver SDV may generate scan signals, and the scan signals maybe applied to the pixels PX through the scan lines SL1 to SLm. The datadriver DDV may generate data voltages, and the data voltages may beapplied to the pixels PX through the data lines DL1 to DLn. The emissiondriver EDV may generate emission signals, and the emission signals maybe applied to the pixels PX through the emission lines EL1 to ELm.

The pixels PX may receive the data voltages in response to the scansignals. The pixels PX may emit light having luminance corresponding tothe data voltages in response to the emission signals to thus display animage. The pixels PX may have an emission time that may be controlled bythe emission signals.

FIG. 6 is a schematic cross-sectional view taken along line I-I′ of FIG.1 .

Referring to FIG. 6 , the display device DD may include a display moduleDM, a support plate SPT, a cushion layer CUL, an insulating tape ITP, animpact absorbing layer ISL, and a black coating layer BCT. The displaymodule DM may include the first non-folding area NFA1, the folding areaFA, and the second non-folding area NFA2, which are arranged in thefirst direction DR1, like the display device DD.

The folding area FA may include a curved part CSP, a first extensionpart EX1 disposed between the curved part CSP and the first non-foldingarea NFA1, and a second extension part EX2 disposed between the curvedpart CSP and the second non-folding area NFA2. Further detailed shapesof the curved part CSP, the first non-folding area NFA1, and the secondnon-folding area NFA2 will be described below.

The support plate SPT may be disposed below the display module DM. Thesupport plate SPT may include a metal material such as stainless steel.Although the support plate SPT may include STS316 as an example, theembodiment is not limited thereto. For example, the support plate SPTmay include various metal materials. The support plate SPT may supportthe display module DM. In addition, the support plate SPT may increasethe heat dissipation performance of the display device DD.

The support plate SPT may include a first support plate SPT1 disposedbelow the first non-folding area NFA1 and a second support plate SPT2disposed below the second non-folding area NFA2. The first support plateSPT1 and the second support plate SPT2 may each extend below the foldingarea FA and may be spaced apart from each other.

The first support plate SPT1 may extend below the first extension partEX1 and the curved part CSP. The second support plate SPT2 may extendbelow the second extension part EX2 and the curved part CSP. The firstsupport plate SPT1 and the second support plate SPT2 may be spaced apartfrom each other below the curved part CSP.

The cushion layer CUL may be disposed below the support plate SPT. Thecushion layer CUL may absorb an external impact applied to a lowerportion of the display module DM to protect the display module DM. Thecushion layer CUL may include a foam sheet having a predeterminedelastic force. The cushion layer CUL may include foam, sponge,polyurethane, or thermoplastic polyurethane.

The cushion layer CUL may include a first cushion layer CUL1 disposedbelow the first support plate SPT1 and a second cushion layer CUL2disposed below the second support plate SPT2. The first cushion layerCUL1 and the second cushion layer CUL2 may each extend below the foldingarea FA and may be spaced apart from each other.

The insulating tape ITP may be disposed below the cushion layer CUL. Theinsulating tape ITP may include an insulating material. The insulatingtape ITP may include a first insulating tape ITP1 disposed below thefirst cushion layer CUL1 and a second insulating tape ITP2 disposedbelow the second cushion layer CUL2. The first insulating tape ITP1 andthe second insulating tape ITP2 may each extend below the folding areaFA and may be spaced apart from each other.

The impact absorbing layer ISL may be disposed below the cushion layerCUL. The impact absorbing layer ISL may be disposed adjacent to an edgeof the cushion layer CUL. The impact absorbing layer ISL may be disposedfurther than the insulating tape ITP. The impact absorbing layer ISL mayabsorb an external impact applied to the edge of the display device DD.The impact absorbing layer ISL may include a pressure sensitive adhesive(PSA).

The impact absorbing layer ISL may include a first impact absorbinglayer ISL1 disposed below the first cushion layer CUL1 and a secondimpact absorbing layer ISL2 disposed below the second cushion layerCUL2. The first impact absorbing layer ISL1 may be disposed further thanthe first insulating tape ITP1. The second impact absorbing layer ISL2may be disposed further than the second insulating tape ITP2. Thus, thefirst and second insulating tapes ITP1 and ITP2 may be disposed betweenthe first impact absorbing layer ISL1 and the second impact absorbinglayer ISL2.

The black coating layer BCT may be disposed between the display moduleDM and the support plate SPT. The black coating layer BCT may be coatedon each of a top surface of the first support plate SPT1 and a topsurface of the second support plate SPT2. The black coating layer BCTmay include a black material. The black coating layer BCT may preventstructures disposed therebelow from being seen from above.

The display module DM may include the display panel DP, a reflectionpreventing layer RPL, a window WIN, a window protection layer WP, apanel protection layer PPL, and a printed layer PIT. The display panelDP according to an embodiment may be a light emitting display panel. Forexample, the display panel DP may be an organic light emitting displaypanel or a quantum dot light emitting display panel. The organic lightemitting display panel may include a light emitting layer containing anorganic light emitting material. The quantum dot light emitting displaypanel may include a light emitting layer containing a quantum dot or aquantum rod. Hereinafter, the display panel DP will be described as theorganic light emitting display panel.

The display panel DP may be a flexible display panel. The display panelDP may include a first non-folding area NFA1, a folding area FA, and asecond non-folding area NFA2, which are arranged in the first directionDR1, like the display module DM. Also, the folding area FA of thedisplay panel DP may include a curved part CSP, a first extension partEX1, and a second extension part EX2 like the display module DM. Thedisplay panel DP may include pixels for displaying an image. The pixelsmay include organic light emitting elements.

The reflection preventing layer RPL may be disposed on the display panelDP. The reflection preventing layer RPL may be disposed directly on thedisplay panel DP. However, the embodiment is not limited thereto. Forexample, the reflection preventing layer RPL may be manufactured as aseparate panel and attached to the display panel DP by using anadhesive.

The reflection preventing layer RPL may be defined as an external lightreflection preventing film. The reflection preventing layer RPL mayreduce a reflectance of external light incident to the display panel DPfrom above the display device DD.

In a case that the external light incident to the display panel DP isreflected by the display panel DP and redirected to an external user,the user may recognize the external light. To prevent theabove-described phenomenon, the reflection preventing layer RPL mayinclude color filters displaying the same color as the pixels.

The color filters may filter out external light to display the samecolor as the pixels. The external light may not be recognized by theuser. However, the embodiment is not limited thereto. For example, thereflection preventing layer RPL may include a phase retarder and/or apolarizer.

The window WIN may be disposed on the reflection preventing layer RPL.The window WIN may protect the display panel DP and the reflectionpreventing layer RPL from external scratches. The window WIN may beoptically transparent. The window WM may include glass. The window WINmay be defined as an ultra-thin glass (UTG). However, the embodiment isnot limited thereto. For example, the window WIN may include a syntheticresin film.

The window protection layer WP may be disposed on the window WIN. Thewindow protection layer WP may protect the window WIN. The windowprotection layer WP may include a flexible plastic material such aspolyimide (PI) or polyethylene terephthalate (PET). Although not shown,a hard coating layer may be provided on the window protection layer WP.In addition, an anti-fingerprint layer or an anti-scattering layer,which is defined as a functional layer, may be provided on the windowprotection layer WP.

The panel protection layer PPL may be disposed below the display panelDP. The panel protection layer PPL may protect a lower portion of thedisplay panel DP. The panel protection layer PPL may include a flexibleplastic material. For example, the panel protection layer PPL mayinclude polyethylene terephthalate (PET).

The display device DD may include first to fourth adhesive layers AL1 toAL4. The first adhesive layer AL1 may be disposed between the windowprotection layer WP and the window WIN. The second adhesive layer AL2may be disposed between the window WIN and the reflection preventinglayer RPL. The third adhesive layer AL3 may be disposed between thedisplay panel DP and the panel protection layer PPL.

The fourth adhesive layer AL4 may be disposed between the panelprotection layer PPL and the support plate SPT. In detail, the fourthadhesive layer AL4 may be disposed between the panel protection layerPPL and the black coating layer BCT.

Each of the first to fourth adhesive layers AL1 to AL4 may include atransparent adhesive such as a pressure sensitive adhesive (PSA) or anoptically clear adhesive (OCA).

The window protection layer WP and the window WIN may be attached toeach other by the first adhesive layer AL1. The window WIN and thereflection preventing layer RPL may be attached to each other by thesecond adhesive layer AL2. The display panel DP and the panel protectionlayer PPL may be attached to each other by the third adhesive layer AL3.

The panel protection layer PPL and the support plate SPT may be attachedto each other by the fourth adhesive layer AL4. In detail, the panelprotection layer PPL may be attached to the black coating layer BCT bythe fourth adhesive layer AL4.

The printed layer PIT may be disposed on a bottom surface of the windowprotection layer WP. The printed layer PIT may overlap the non-displayarea NDA when viewed on the plane. The first adhesive layer AL1 may bedisposed below the window protection layer WP to cover or overlap theprinted layer PIT. Although the printed layer PIT may have a black coloras an example, the embodiment is not limited thereto. For example, theprinted layer PIT may have various colors.

When viewed on the plane, the fourth adhesive layer AL4 may overlap thefirst and second non-folding areas NFA1 and NFA2. In addition, whenviewed on the plane, the fourth adhesive layer AL4 may overlap the firstand second extension parts EX1 and EX2 and may not overlap the curvedpart CSP. Thus, the first and second support plates SPT1 and SPT2 may beattached to the first and second non-folding areas NFA1 and NFA2 and thefirst and second extension parts EX1 and EX2 and may not be attached tothe curved part CSP.

In the third direction DR3, the reflection preventing layer RPL may havea thickness less than that of the display panel DP, the window WIN mayhave a thickness greater than that of the display panel DP, and thewindow protection layer WP may have a thickness greater than that of thewindow WIN. In the third direction DR3, the first adhesive layer AL1 mayhave the same thickness as that of the second adhesive layer AL2. Inaddition, each of the first adhesive layer AL1 and the second adhesivelayer AL2 may have a thickness greater than that of the window WIN andless than that of the window protection layer WP.

In the third direction DR3, the panel protection layer PPL may have thesame thickness as that of the window WIN, and the third adhesive layerAL3 may have a thickness less than that of the display panel DP andgreater than that of the reflection preventing layer RPL. In the thirddirection DR3, the fourth adhesive layer AL4 may have a thickness lessthan that of the third adhesive layer AL3 and greater than that of thereflection preventing layer RPL.

In the third direction DR3, the window WIN may have a thickness greaterthan about 30 μm and less than about or equal to 80 μm, and the windowprotection layer WP may have a thickness in a range from about 55 μm toabout 100 μm. In the third direction DR3, the support plate SPT may havea thickness in a range from about 80 μm to about 150 μm

In the third direction DR3, the support plate SPT may have a thicknessgreater than that of the window WIN. In the third direction DR3, thecushion layer CUL may have a thickness equal to or greater than that ofthe support plate SPT. In the third direction DR3, each of theinsulating tape ITP and the impact absorbing layer ISL may have the samethickness as that of the panel protection layer PPL.

In the first direction DR1 and the second direction DR2, the windowprotection layer WP may have a width greater than that of the windowWIN. In the first direction DR1 and the second direction DR2, each ofthe display panel DP, the reflection preventing layer RPL, and the panelprotection layer PPL may have a width greater than that of the windowprotection layer WP.

In the first direction DR1 and the second direction DR2, the displaypanel DP, the reflection preventing layer RPL, and the panel protectionlayer PPL may have the same width as each other. In the first directionDR1 and the second direction DR2, the first adhesive layer AL1 may havethe same width as that of the window protection layer WP, and the secondadhesive layer AL2 may have a width less than that of the window WIN.

Since the window WIN and the second adhesive layer AL2 between thewindow protection layer WP and the display panel DP have differentwidths, the difference in width therebetween may form a steppedstructure therebetween. The window protection layer WP may have athickness sufficient to prevent the stepped structure from beingrecognized from the outside. For example, in a case that the windowprotection layer WP has a thickness in a range from about 55 μm to about100 μm, the stepped structure may not be recognized from the outside.

When viewed on the plane, each of the first and second support platesSPT1 and SPT2, the first and second cushion layers CUL1 and CUL2, thefirst and second insulating tapes ITP1 and ITP2, and the first andsecond impact absorbing layers ISL1 and ISL2 may be disposed at an innerside more than the edge of the display panel DP.

FIG. 7 is a schematic cross-sectional view illustrating the displaypanel DP in FIG. 6 .

Referring to FIG. 7 , the display panel DP may include a substrate SUB,a circuit element layer DP-CL disposed on the substrate SUB, a displayelement layer DP-OLED disposed on the circuit element layer DP-CL, athin-film encapsulation layer TFE disposed on the display element layerDP-OLED, and an input sensing part ISP disposed on the thin-filmencapsulation layer TFE.

The substrate SUB may include a display area DA and a non-display areaNDA around the display area DA. The substrate SUB may include a flexibleplastic material. For example, the substrate SUB may include polyimide(PI). The display element layer DP-OLED may be disposed on the displayarea DA.

The circuit element layer DP-CL may include an insulation layer, asemiconductor pattern, a conductive pattern, and a signal line. Each ofthe insulation layer, the semiconductor layer, and the conductive layermay be provided on the substrate SUB through coating, deposition, andthe like within the spirit and the scope of the disclosure. Thereafter,the insulation layer, the semiconductor layer, and the conductive layermay be selectively patterned through photolithography processes toprovide the semiconductor pattern, the conductive pattern, and thesignal line.

The circuit element layer DP-CL may include transistors constituted bythe semiconductor pattern, the conductive pattern, and the signal line.The display element layer DP-OLED may include light emitting elementselectrically connected to the transistors. The pixels PX may include thetransistors and the light emitting elements.

The thin-film encapsulation layer TFE may be disposed on the circuitelement layer DP-CL to cover or overlap the display element layerDP-OLED. The thin-film encapsulation layer TFE may include an inorganiclayer, an organic layer, and an inorganic layer, which are sequentiallylaminated with each other. The inorganic layers may contain an inorganicmaterial and protect the pixels PX from moisture or oxygen. The organiclayer may contain an organic material and protect the pixels PX fromforeign substances such as dust particles.

The input sensing part ISP may include sensors (not shown) for sensingan external input. The sensors may sense the external input by acapacitive method. The external input may include various types ofinputs using a portion of a user's body, light, heat, a pen, orpressure.

The input sensing part ISP may be manufactured on the thin-filmencapsulation layer TFE in a case that the display panel DP ismanufactured. However, the embodiment is not limited thereto. Forexample, the input sensing part ISP may be manufactured on a paneldistinct from the display panel DP and then attached to the displaypanel DP by an adhesive layer.

FIGS. 8 to 10 are views illustrating various bent states of the displaymodule and the support plates.

FIGS. 8 to 10 show results obtained by performing tests for the curvedpart CSP of the display module DM to have a specific or predeterminedcurvature.

For example, the display module DM and support plates SPT_1 to SPT_3 forsupporting the display module DM are illustrated in FIGS. 8 to 10 . Thesupport plates SPT_1 to SPT_3 may have the same configuration as thesupport plate SPT in FIG. 6 . However, the support plates SPT_1 to SPT_3may have different thicknesses.

The cushion layer CUL, the insulating tape ITP, and the impact absorbinglayer ISL, which are disposed below the support plates SPT_1 to SPT_3,are omitted for convenience of description. In addition, the blackcoating layer BCT disposed on the support plates SPT_1 to SPT_3 isomitted.

Referring to FIGS. 8 to 10 , jigs JIG1 and JIG2 may be used to fold thedisplay module DM. Each of the support plates SPT_1 to SPT_3 may have athickness in a range from about 80 μm to about 150 μm like the supportplate SPT. The support plates SPT_1 to SPT_3 may have differentthicknesses.

The support plate SPT_1 in FIG. 8 may have a first thickness TH1 greaterthan a second thickness TH2 of the support plate SPT_2 in FIG. 9 . Thesecond thickness TH2 of the support plate SPT_2 in FIG. 9 may be greaterthan a third thickness TH3 of the support plate SPT_3 in FIG. 10 .

Each of a length of the folding area FA and lengths of the first andsecond non-folding areas NFA1 and NFA2 may be varied according topositions of the jigs JIG1 and JIG2 contacting the display module DM.

Hereinafter, a virtual line extending toward the curved part CSP fromthe first non-folding area NFA1 in the same direction (e.g. thirddirection DR3) as an extension direction of the first non-folding areaNFA1 when the display module DM may be folded may be defined as a firstreference line RFL1. In addition, a virtual line extending toward thecurved part CSP from the second non-folding area NFA2 in the samedirection (e.g. third direction DR3) as an extension direction of thesecond non-folding area NFA2 when the display module DM may be foldedmay be defined as a second reference line RFL2.

Hereinafter, bent points between the first extension part EX1 and thefirst non-folding area NFA1 may be defined as first points P1_1, P1_2,and P1_3. In addition, bent points between the second extension part EX2and the second non-folding area NFA2 may be defined as second pointsP21, P2_2, and P2_3.

Referring to FIG. 8 , as the display module DM is folded by using thejigs JIG1 and JIG2, the folding area FA may be bent. The jigs JIG1 andJIG2 may include a first jig JIG1 and a second jig JIG2. The first jigJIG1 may be disposed at a boundary between the folding area FA and thefirst non-folding area NFA1, and the second jig JIG2 may be disposed ata boundary between the folding area FA and the second non-folding areaNFA2.

As the first and second jigs JIG1 and JIG2 move to be adjacent to eachother, the first non-folding area NFA1 and the second non-folding areaNFA2 may be adjacent to each other. In a case that the display module DMis folded, the first and second non-folding area NFA1 and NFA2 may eachextend in the third direction DR3.

In a case that the display module DM is folded, the folding area FA mayinclude the bent curved part CSP, the first extension part EX1 disposedbetween the curved part CSP and the first non-folding area NFA1, and thesecond extension part EX2 disposed between the curved part CSP and thesecond non-folding area NFA2.

The curved part CSP may be bent to have a predetermined curvature. Indetail, in a case that the display module DM is folded, the curved partCSP may be bent to have a predetermined radius Rc of curvature(hereinafter, referred to as a predetermined curvature radius Rc).

The first extension part EX1 may be bent from the first non-folding areaNFA1 by the first jig JIG1 and may extend to the curved part CSP. Thesecond extension part EX2 may be bent from the second non-folding areaNFA2 by the second jig JIG2 and may extend to the curved part CSP.

A distance DT between the first non-folding area NFA1 and the secondnon-folding area NFA2 may be less than the curvature radius Rc. By theabove-described structure, the display module DM may be folded into asubstantially dumbbell shape.

The support plate SPT_1 may include a first support plate SPT1_1disposed on the first extension part EX1 and a second support plateSPT2_1 disposed on the second extension part EX2.

In a case that the display module DM is folded, the first support plateSPT1_1 may be bent at the first point P1_1 by the first jig JIG1. Thefirst support plate SPT1_1 may be bent at a boundary between the foldingarea FA and the first non-folding area NFA1 by the first jig JIG1.

In a case that the display module DM is folded, the second support plateSPT2_1 may be bent at the second point P2_1 by the second jig JIG2. Thesecond support plate SPT2_1 may be bent at a boundary between thefolding area FA and the second non-folding area NFA2 by the second jigJIG2.

Since the first support plate SPT1_1 is attached to the first extensionpart EX1 by the fourth adhesive layer AL4 in FIG. 6 , the firstextension part EX1 may maintain a flat state by the first support plateSPT1_1. Since the second support plate SPT2_1 is attached to the secondextension part EX2 by the fourth adhesive layer AL4 in FIG. 6 , thesecond extension part EX2 may maintain a flat state by the secondsupport plate SPT2_1.

As previously described in FIG. 6 , the curved part CSP may not beattached to the first and second support plates SPT1_1 and SPT2_1. Thus,the curved part CSP may be bent in a case that the display module DM isfolded.

The first extension part EX1 may make a first angle θ1_1 with the firstreference line RFL1. The second extension part EX2 may make a secondangle θ2_1 with the second reference line RFL2. Each of the first angleθ11 and the second angle θ2_1 may be an acute angle. In a case that thedisplay module DM is folded, the first extension part EX1 and the secondextension part EX2 may extend to be symmetric to each other. Thus, thefirst angle θ1_1 may be equal to the second angle θ2_1. However, anembodiment is not limited thereto. For example, the first angle θ1_1 maybe different from the second angle θ2_1.

The curved part CSP may be bent to have a desired or predeterminedcurvature radius RC according to a bent angle of the support plateSPT_1. The bent angle of the support plate SPT_1 may be the first angleθ1_1 and the second angle θ21 and may be varied according to thethickness TH1 of the support plate SPT_1.

In a case that the display module DM is folded, a stress generated inthe folding area FA may push the support plate SPT_1 to the outside.However, the support plate SPT_1 having a greater thickness may have ahigh resistance against the stress generated in the folding area FA.

A bent point of the support plate SPT_1 may be transferred from thefirst and second points P1_1 and P2_1 to first and second points P1′ andP2′, which may be closer to the curved part CSP, in FIG. 8 . The curvedpart CSP may be bent to have a large or great curvature as illustratedby a dotted line by the resistance according to the thickness TH1 of thesupport plate SPT_1 illustrated by a dash-dotted line, thereby having acurvature radius less than the curvature radius Rc. The curved part CSPmay not be bent at the desired or predetermined curvature.

A distance between the first point P1_1 and the second point P2_1 may bedefined as that from the first point P1_1 to the second point P2_1 alongthe display module DM. The distance between the first point P1_1 and thesecond point P2_1 may be defined as a length of the folding area FA in acase that the folding area FA is unfolded. A distance between the firstpoint P1′ and the second point P2′ may be defined as a distance from thefirst point P1′ to the second point P2′ along the display module DM.

The distance between the first point P1_1 and the second point P2_1 maybe less than that between the first point P1′ and the second point P2′.The curvature radius Rc of the curved part CSP may be varied accordingto distances between the bent points P1_1, P2_1, P1′, and P2′ of thesupport plate SPT_1.

In summary, the curvature radius Rc of the curved part CSP may be variedaccording to the bent angle θ1_1 and θ2_1 of the support plate SPT_1,the thickness TH1 of the support plate SPT_1, and the distance betweenthe bent points P1_1 and P2_1 of the support plate SPT_1.

Hereinafter, in FIGS. 9 and 10 , different components from those in FIG.8 and a structure of each of the support plates SPT_2 and SPT_3 havingthe curvature radius Rc will be mainly described.

Referring to FIG. 9 , the support plate SPT_2 may include a firstsupport plate SPT1_2 and a second support plate SPT2_2. The supportplate SPT_2 may have a second thickness TH2 less than the firstthickness TH1. Since the support plate SPT_2 may have a smallerthickness, the support plate SPT_2 may have a resistance less than thatof the support plate SPT_1 in FIG. 8 against the stress generated in thefolding area FA.

The first support plate SPT1_2 and the second support plate SPT2_2 maybe bent at the first point P1_2 and the second point P2_2, respectively,which may be closer to the curved part CSP than to the first point P1_1and the second point P2_1 in FIG. 8 so that the curved part CSP has thecurvature radius Rc.

A distance between the first point P1_2 and the second point P2_2 may bedefined as that from the first point P1_2 to the second point P2_2 alongthe display module DM. The distance between the first point P1_2 and thesecond point P2_2 may be less than that between the first point P1_1 andthe second point P2_1. Thus, a first angle θ1_2 and a second angle θ2_2may be greater than the first angle θ1_1 and the second angle θ2_1 inFIG. 8 , respectively.

Referring to FIG. 10 , the support plate SPT_3 may include a firstsupport plate SPT1_3 and a second support plate SPT2_3. The supportplate SPT_3 may have a third thickness TH3 less than the secondthickness TH2. Since the support plate SPT_3 may have a smallerthickness, the support plate SPT_3 may have a resistance less than thatof the support plate SPT_2 in FIG. 9 against the stress generated in thefolding area FA.

The first support plate SPT1_3 and the second support plate SPT2_3 maybe bent at the first point P1_3 and the second point P2_3, respectively,which may be closer to the curved part CSP than to the first point P1_2and the second point P2_2 in FIG. 9 so that the curved part CSP has thecurvature radius Rc.

A distance between the first point P1_3 and the second point P2_3 may bedefined as that from the first point P1_3 to the second point P2_3 alongthe display module DM. The distance between the first point P1_3 and thesecond point P2_3 may be less than that between the first point P1_2 andthe second point P2_2. Thus, a first angle θ1_3 and a second angle θ2_3may be greater than the first angle θ1_2 and the second angle θ22 inFIG. 9 , respectively.

Referring to FIGS. 8, 9, and 10 , the curvature radius Rc of the curvedpart CSP may be set to a range of about 1.5 mm to about 5.0 mm, as anexample, about 2.5 mm. The distance between the first points P1_1, P1_2,and P1_3 and the second points P21, P2_2, and P2_3 may be set to a rangeof about 35 mm to about 45 mm, as an example about 40 mm. The distancebetween the first points P1_1, P1_2, and P1_3 and the second points P21,P2_2 and P2_3 may be substantially defined as the length of the foldingarea FA.

The first angles θ1_1, θ1_2, and θ1_3 may be set toa range of about 6.5°to about 12.5°, as an example about 9.5°, so that the curved part CSPhas the curvature radius Rc. The second angles θ2_1, θ2_2, and θ2_3 maybe about equal to the first angles θ1_1, θ1_2, and θ1_3, respectively.The thicknesses TH1, TH2, and TH3 of the support plates SPT_1, SPT_2,and SPT_3 may be set to a range of about 80 μm to about 150 μm, as anexample about 80 μm, so that the curved part CSP has the curvatureradius Rc. Effects caused by the above numerical values will bedescribed in detail below.

FIGS. 11 and 12 are exploded perspective views illustrating a support onwhich the display module DM and the support plate SPT in FIG. 6 aredisposed. FIG. 13 is a plan view illustrating the support obtained bycoupling first and second supports, first and second wing plates, and ahinge in FIGS. 11 and 12 .

FIG. 11 is an upper exploded perspective view illustrating a support SUPwhen viewed from above the support SUP, and FIG. 12 is a lower explodedperspective view illustrating the support SUP when viewed from below thesupport SUP.

Referring to FIGS. 11, 12, and 13 , the display device DD may includethe support SUP, and the support SUP may include a first support SUP1, asecond support SUP2, a first wing plate WPT1, a second wing plate WPT2,and a hinge HIG. The first support SUP1 and the second support SUP2 maybe arranged in the first direction DR1. The first support SUP1 and thesecond support SUP2 may have a plane defined by the first and seconddirections DR1 and DR2.

A recessed portion RES may be defined in a top surface of the firstsupport SUP1. Although not shown, various components may be disposed inthe recessed portion RES. For example, a battery for supplying power tothe display module DM or a system board for providing a driving signalto the display module DM may be disposed in the recessed portion RES. Anopening OP disposed adjacent to the recessed portion RES may be definedin the first support SUP1. A sensor or a camera may be disposed in theopening OP.

The top surface of the first support SUP1 may be adjacent to a side OS1of the first support SUP1, facing the second support SUP2 and may have afirst inclined surface SLP1. The first inclined surface SLP1 may have aheight that gradually decreases in a direction toward the side OS1 ofthe first support SUP1. The recessed portion RES may be adjacent to thefirst inclined surface SLP1.

A top surface of the second support SUP2 may be adjacent to a side OS2of the second support SUP2, facing the first support SUP1 and may have asecond inclined surface SLP2. The second inclined surface SLP2 may havea height that gradually decreases in a direction toward the side OS2 ofthe second support SUP2.

The first wing plate WPT1 may be disposed on the first support SUP1 andconnected to the first support SUP1. The first wing plate WPT1 may bedisposed on the first inclined surface SLP1 and rotatably coupled to anupper side of the first inclined surface SLP1, which is the most awayfrom the side OS1 of the first support SUP1.

A first connection pin PIN1 extending in the second direction DR2 andconnected to the first support SUP1 may be disposed at a side of thefirst wing plate WPT1. The side of the first wing plate WPT1 may overlapthe upper side of the first inclined surface SLP1. The first connectionpin PIN1 may have a substantially cylindrical shape extending in thesecond direction DR2.

The second wing plate WPT2 may be disposed on the second support SUP2and connected to the second support SUP2. The second wing plate WPT2 maybe disposed on the second inclined surface SLP2 and rotatably coupled toan upper side of the second inclined surface SLP2, which is the mostaway from the side OS2 of the second support SUP2.

A second connection pin PIN2 extending in the second direction DR2 andconnected to the second support SUP2 may be disposed at a side of thesecond wing plate WPT2. The side of the second wing plate WPT2 mayoverlap the upper side of the second inclined surface SLP2. The secondconnection pin PIN2 may have a substantially cylindrical shape extendingin the second direction DR2.

The hinge HIG may be connected to the first support SUP1 and the secondsupport SUP2. The hinge HIG may include a biaxial rotation shaft RX1 andRX2 between the first support SUP1 and the second support SUP2. Thebiaxial rotation shaft RX1 and RX2 may include a first rotation shaftRX1 and a second rotation shaft RX2, which may be spaced apart from eachother in the first direction DR1 and may extend in parallel to eachother in the second direction DR2.

The hinge HIG may include hinge parts HGP, a cover part CVP, and firstand second rotation units RU1 and RU2. The hinge parts HGP may beconnected to sides of the first support SUP1, which may be opposite toeach other, and sides of the second support SUP2, which may be oppositeto each other.

For example, coupling grooves CGV may be defined in the sides of thefirst support SUP1 and the sides of the second support SUP2, and thehinge parts HGP may be disposed in the coupling grooves CGV. Thecoupling grooves CGV may be defined from the side OS1 of the firstsupport SUP1 and the side OS2 of the second support SUP2. Although notshown, connection pins for coupling the hinge parts HGP to the couplinggrooves CGV may be provided on the hinge parts HGP.

The cover part CVP may extend in the second direction DR2 and may bedisposed between the first support SUP1 and the second support SUP2. Agroove GOV extending in the second direction DR2 may be defined in thecover part CVP.

A pair of the first and second rotation units RU1 and RU2 may beconnected to ends of the cover part CVP, respectively, which areopposite to each other in the second direction DR2. Each of the ends ofthe cover part CVP, which are opposite to each other in the seconddirection DR2, may have a substantially sidewall shape. The pair of thefirst and second rotation units RU1 and RU2 may be spaced apart fromeach other in the first direction DR1 and may each extend in the seconddirection DR2.

The first rotation shaft RX1 may be defined by the first rotation unitRU1, and the second rotation shaft RX2 may be defined by the secondrotation unit RU2. The first rotation unit RU1 may rotate around thefirst rotation shaft RX1, and the second rotation unit RU2 may rotatearound the second rotation shaft RX2.

The hinge part HGP may be connected to the first and second rotationunits RU1 and RU2. In detail, sides of the hinge parts HGP facing eachother in the first direction DR1 may be connected to the first rotationunit RU1 and the second rotation unit RU2. Thus, the hinge parts HGP mayrotate around the first and second rotation shafts RX1 and RX2 by thefirst and second rotation units RU1 and RU2.

For example, two hinge parts HGP arranged in the first direction DR1 maybe connected to the pair of first and second rotation units RU1 and RU2.In addition, other two hinge parts HGP arranged in the first directionDR1 may be connected to the other pair of first and second rotationunits RU1 and RU2.

FIG. 14 is a perspective view illustrating the support in FIG. 13 . FIG.15 is a view illustrating a folded state of the support in FIG. 14 .

Referring to FIGS. 14 and 15 , the hinge parts HGP connected to thefirst and second rotation units RU1 and RU2 may rotate around the firstand second rotation shafts RX1 and RX2 so that the support part SUP isfolded. The first and second supports SUP1 and SUP2 connected to thehinge parts HGP may move while rotating around the first and secondrotation shafts RX1 and RX2 as the hinge parts HGP rotate.

The first support SUP1 and the second support SUP2 may move by rotatingin opposite directions. The first support SUP1 may move by rotating in aclockwise direction around the first rotation shaft RX1. The secondsupport SUP2 may move by rotating in a counterclockwise direction aroundthe second rotation shaft RX2. Thus, as the support SUP is folded, thetop surface of the first support SUP1 and the top surface of the firstsupport SUP1 may face each other.

FIG. 16 is a schematic cross-sectional view taken along line II-II′ ofFIG. 14 . FIG. 17 is a view illustrating a folded state of the displaydevice in FIG. 16 .

As an example, the display module DM and the support plate SPT areillustrated in conjunction with the support SUP in FIGS. 16 and 17 . Inaddition, the cushion layer CUL, the insulating tape ITP, the impactabsorbing layer ISL, which are disposed below the support plate SPT, andthe black coating layer BCT disposed on the support plate SPT areomitted.

Referring to FIG. 16 , the display module DM and the support plate SPTmay be disposed on the support SUP. The display module DM and thesupport plate SPT may be in an unfolded state that is defined as a flatstate. The first and second rotation shafts RX1 and RX2 may be definedbelow the curved part CSP of the folding area FA.

In a case that the display module DM is in the unfolded state, thefolding area FA may have a length of about 35 mm to about 45 mm in thefirst direction DR1. The distance between the first points P1_1, P1_2,and P1_3 and the second points P21, P2_2, and P2_3 may be substantiallydefined as the length of the folding area FA.

In a case that the display module DM is in the unfolded state, each ofthe first and second support plates SPT1 and SPT2 may have a thicknessof about 80 μm to about 150 μm in the third direction DR3. Therespective thicknesses of the first and second support plates SPT1 andSPT2 may be the above-described first, second, and third thicknessesTH1, TH2, and TH3.

The first support SUP1 may be disposed below the first non-folding areaNFA1. The second support SUP2 may be disposed below the secondnon-folding area NFA2. The first support plate SPT1 may be disposedbetween the first support SUP1 and the first non-folding area NFA1. Thesecond support plate SPT2 may be disposed between the second supportSUP2 and the second non-folding area NFA2.

The first support plate SPT1 may extend below the first extension partEX1, and the second support plate SPT2 may extend below the secondextension part EX2. When viewed on the plane while facing the firstextension part EX1, the top surface of the first support SUP1overlapping the first extension part EX1 may be defined as the firstinclined surface SLP1. When viewed on the plane while facing the secondextension part EX2, the top surface of the second support SUP2overlapping the second extension part EX2 may be defined as the secondinclined surface SLP2.

The first wing plate WPT1 may be disposed between the first extensionpart EX1 and the first inclined surface SLP1. The first wing plate WPT1may be rotatably coupled to a portion of the first support SUP1overlapping a boundary between the first non-folding area NFA1 and thefirst extension part EX1 when viewed on the plane.

The first wing plate WPT1 may rotate around a third rotation shaft RX3extending in the second direction DR2. The third rotation shaft RX3 maybe defined by the first connection pin PIN1. The portion of the firstsupport SUP1, which overlaps the boundary between the first non-foldingarea NFA1 and the first extension part EX1, may be defined as the upperside of the first inclined surface SLP1.

The second wing plate WPT2 may be disposed between the second extensionpart EX2 and the second inclined surface SLP2. The second wing plateWPT2 may be rotatably coupled to a portion of the second support SUP2overlapping a boundary between the second non-folding area NFA2 and thesecond extension part EX2 when viewed on the plane.

The second wing plate WPT2 may rotate around a fourth rotation shaft RX4extending in the second direction DR2. The fourth rotation shaft RX4 maybe defined by the second connection pin PIN2. The portion of the secondsupport SUP2, which overlaps the boundary between the second non-foldingarea NFA2 and the second extension part EX2, may be defined as the upperside of the second inclined surface SLP2.

The first wing plate WPT1 and the second wing plate WPT2 may besymmetric to each other. The first inclined surface SLP1 and the secondinclined surface SLP2 may be symmetric to each other. A distance betweenthe first wing plate WPT1 and the first inclined surface SLP1 mayincrease in a direction toward the curved part CSP while the displaymodule DM and the support SUP are unfolded. In addition, a distancebetween the second wing plate WPT2 and the second inclined surface SLP2may increase in a direction toward the curved part CSP while the displaymodule DM and the support SUP are unfolded.

The first wing plate WPT1 and the first inclined surface SLP1 may make afirst angle θ1 while the display module DM and the support SUP areunfolded. The first angle θ1 may be in a range from about 6.5° to about12.5°. The first angle θ1 may be equal to the above-described firstangles θ1_1, θ1_2, or θ1_3. A second angle θ2 between the second wingplate WPT2 and the second inclined surface SLP2 may be equal to thefirst angle θ1.

A structure of the support SUP may be determined depending on the testresults described in FIGS. 8 to 10 . For example, the first and secondwing plates WPT1 and WPT2 may overlap the folding area FA having alength of about 35 mm to about 45 mm. In addition, the first angle θ1between the first inclined surface SLP1 and the first wing plate WPT1may be determined as the above-described first angles θ1_1, θ1_2, orθ1_3. The first angles θ1_1, θ1_2, and θ1_3 may be numerical valuesdetermined in consideration of the thicknesses TH1, TH2, and TH3 of thesupport plates SPT_1, SPT_2, and SPT_3.

The cover part CVP may be disposed between the first support SUP1 andthe second support SUP2. The cover part CVP may be disposed below thefirst and second wing plates WPT1 and WPT2. A portion of the first wingplate WPT1 and a portion of the second wing plate WPT2 may be disposedon the cover part CVP. The groove GOV defined in the cover part CVP mayface the curved part CSP.

The first rotation shaft RX1 and the second rotation shaft RX2 mayoverlap the curved part CSP and the groove GOV when viewed on the plane.In addition, the first rotation shaft RX1 and the second rotation shaftRX2 may overlap the groove GOV when viewed in the second direction DR2.

Referring to FIG. 17 , as the first and second supports SUP1 and SUP2rotate around the first and second rotation shafts RX1 and RX2,respectively, the display module DM may be folded. The folding area FAmay be bent to have a curvature radius Rc in a range of about 1.5 mm toabout 5.0 mm. The display module DM may be in-folded so that the firstnon-folding area NFA1 and the second non-folding area NFA2 face eachother. The distance DT between the first non-folding area NFA1 and thesecond non-folding area NFA2 may be less than the curvature radius Rc.

In a case that the display module DM is folded, the first wing plateWPT1 may rotate around the third rotation shaft RX3 to contact the firstinclined surface SLP1 according to the stress of the folding area FA. Ina case that the display module DM is folded, the second wing plate WPT2may rotate around the fourth rotation shaft RX4 to contact the secondinclined surface SLP2 according to the stress of the folding area FA.

In a case that the display module DM is folded, the first support plateSPT1 may be bent at the boundary between the first non-folding area NFA1and the first extension part EX1 by the first wing plate WPT1. In a casethat the display module DM is folded, the second support plate SPT2 maybe bent at the boundary between the second non-folding area NFA2 and thesecond extension part EX2 by the second wing plate WPT2.

In a case that the display module DM is folded, a central portion of thecurved part CSP may be disposed in the groove GOV. In addition, in acase that the display module DM is folded, the side of the first wingplate WPT1 and the side of the second wing plate WPT2, which face eachother, may be disposed in the groove GOV.

As described in FIGS. 8 to 10 , in a case that the support plates SPT_1,SPT_2, and SPT_3 are bent at the first angles θ1_1, θ1_2, and θ1_3,respectively, according to the thicknesses TH1, TH2, and TH3 of thesupport plates SPT_1, SPT_2, and SPT_3, the curved part CSP may have apredetermined curvature radius Rc.

As the first wing plate WPT1 and the first inclined surface SLP1 havethe first angle θ1 therebetween in a case that the display module DM isunfolded, and the first wing plate WPT1 and the first inclined surfaceSLP1 contact each other in a case that the display module DM is folded,the first extension part EX1 may form the first angle θ1 with the firstreference line RFL1.

Likewise, as the second wing plate WPT2 contacts the second inclinedsurface SLP2, the second extension part EX2 may form the second angle θ1with the second reference line RFL2. Thus, in a case that the displaymodule DM is folded, the curved part CSP of the folding area FA may bebent to have a curvature radius Re in a range of about 1.5 mm to about5.0 mm.

FIG. 18 is an enlarged photograph showing a folding area of acomparative display module. FIG. 19 is a graph showing a deformed stateof the folding area in FIG. 18 . FIG. 20 is an enlarged photographshowing the folding area of the display module according to anembodiment. FIG. 21 is a graph showing a deformed state of the foldingarea in FIG. 20 .

A comparative display module DM′ in FIG. 18 may be folded instead ofhaving a dumbbell structure and may have a curvature radius differentfrom the curvature radius Rc.

Horizontal axes in FIGS. 19 and 21 represent distances from centralportions of curved parts CSP′ and CSP in the first direction DR1.Vertical axes in FIGS. 19 and 21 represent deformation of the curvedparts CSP′ and CSP in the third direction DR3.

FIGS. 18 and 20 are photographs obtained by photographing the curvedparts CSP′ and CSP in a state in which the comparative display moduleDM′ and the display module DM are folded, the folded state thereof ismaintained for a predetermined time, the comparative display module DM′and the display module DM are unfolded, and a predetermined time haselapsed.

Referring to FIGS. 18 and 19 , a crease CRS' may be generated in thecurved part CSP′ of the comparative display module DM′. A differencebetween a maximum height and a minimum height of the crease CRS' may bedefined as a first deformation STR1.

Referring to FIGS. 20 and 21 , a crease CRS may be generated in thecurved part CSP of the display module DM. A difference between a maximumheight and a minimum height of the crease CRS may be defined as a seconddeformation STR2.

Referring to FIGS. 18 to 21 , the first deformation STR1 of the curvedpart CSP′ may be greater than the second deformation STR2 of the curvedpart CSP. Thus, the crease CRS' generated in the curved part CSP′ may bemore clearly recognized. In addition, the crease CRS generated in thecurved part CSP may not be recognized.

In an embodiment, as the folding area FA is bent into the substantiallydumbbell shape, and the curved part CSP may be bent to have a curvatureradius Rc of about 1.5 mm to about 5.0 mm, and thus deformation of thefolding area FA may be reduced.

FIG. 22 is an enlarged photograph showing a surface of the comparativedisplay module. FIG. 23 is an enlarged photograph showing a surface ofthe display module in FIG. 6 .

A surface of the display module DM may be defined as the top surface ofthe display module DM. A surface of a comparative display module DM″ maybe defined as a top surface of the comparative display module DM″.

FIGS. 22 and 23 are photographs obtained by capturing surfaces by usingOptimap PSD, which is a coating surface measurement analyzer, ofRhopoint instruments.

Referring to FIGS. 22 and 23 , a window of the comparative displaymodule DM″ may have a thickness of about 30 μm. As described above, thewindow WIN of the display module DM may have a thickness greater thanabout 30 μm and equal to or less than about 80 μm. For example, thewindow WIN of the display module DM in FIG. 23 may have a thickness ofabout 50 m.

The window WIN of the display module DM may have a greater thickness.The comparative display module DM″ including the window having a smallerthickness had a surface quality index of about 0.46 Kc. The displaymodule DM including the window WIN having a greater thickness had asurface quality index of about 0.34 Kc.

As the surface quality index (Kc) decreases, an object to be measuredmay have a smoother surface. Thus, the display module DM may have asurface quality index greater than that of the display module DM′. Thedisplay module DM may have a top surface smoother than that of thedisplay module DM′.

According to the embodiment, the deformation of the folding area may bereduced as the folding area is folded to have the curvature radiuscapable of minimizing the deformation of the folding area.

Although embodiments have been described, it is understood that thedisclosure should not be limited to these embodiments but rather variouschanges and modifications can be made by one of ordinary skill in theart within the spirit and scope of the disclosure as hereinafterclaimed. Thus, the scope of the disclosure is to be determined by thebroadest permissible interpretation of the following claims and theirequivalents, and shall not be restricted or limited by the foregoingdetailed description.

What is claimed is:
 1. A display device comprising: a display modulecomprising a first non-folding area, a second non-folding area, and afolding area disposed between the first non-folding area and the secondnon-folding area, the first non-folding area, the second non-foldingarea, and the folding area being arranged in a first direction; a firstsupport disposed below the first non-folding area; a second supportdisposed below the second non-folding area; and a hinge including abiaxial rotation shaft disposed between the first support and the secondsupport, the biaxial rotation shaft extending in a second directionintersecting the first direction, wherein the folding area has acurvature radius in a range of 1.5 mm to 5.0 mm when the display moduleis folded by a rotation of the first support and the second support withrespect to the biaxial rotation shaft, and the folding area has a lengthin a range of 35 mm to 45 mm.
 2. The display device of claim 1, whereinthe length of the folding area is in the first direction when thedisplay module is unfolded.
 3. The display device of claim 1, whereinthe folding area comprises: a curved part bent to have the curvatureradius when the display module is folded; a first extension part bentfrom the first non-folding area to extend to the curved part; and asecond extension part bent from the second non-folding area to extend tothe curved part, wherein a distance between the first non-folding areaand the second non-folding area is less than the curvature radius of thecurved part of the folding area when the display module is folded. 4.The display device of claim 3, wherein the first extension part and thesecond extension part are symmetric when the display module is folded,and the first extension part forms an acute angle with a first referenceline extending from the first non-folding area to the curved part in asame direction as an extension direction of the first non-folding areawhen the display module is folded.
 5. The display device of claim 4,wherein the acute angle is in a range of about 6.5° to about 12.5°. 6.The display device of claim 3, further comprising: a first support platedisposed between the first support and the first non-folding area; and asecond support plate disposed between the second support and the secondnon-folding area, wherein the first support plate extends below thefirst extension part and the curved part, the second support plateextends below the second extension part and the curved part, and thefirst support plate is spaced apart from the second support plate belowthe curved part.
 7. The display device of claim 6, wherein the firstsupport plate and the second support plate are attached to the firstnon-folding area, the second non-folding area, the first extension part,and the second extension part, and the first support plate and thesecond support plate are not attached to the curved part.
 8. The displaydevice of claim 6, wherein the first support plate is bent at a boundarybetween the first non-folding area and the first extension part when thedisplay module is folded, and the second support plate is bent at aboundary between the second non-folding area and the second extensionpart when the display module is folded.
 9. The display device of claim6, wherein each of the first support plate and the second support platehas a thickness in a range of about 80 μm to about 150 μm in a thirddirection perpendicular to a plane defined by the first and seconddirections when the display module is unfolded.
 10. The display deviceof claim 6, further comprising: a black coating layer coated on each ofa top surface of the first support plate and a top surface of the secondsupport plate; a first cushion layer disposed below the first supportplate; and a second cushion layer disposed below the second supportplate.
 11. The display device of claim 3, wherein the first supportextends below the first extension part, the second support extends belowthe second extension part, a top surface of the first support facing thefirst extension part has a first inclined surface in a plan view, and atop surface of the second support facing the second extension part has asecond inclined surface in the plan view.
 12. The display device ofclaim 11, further comprising: a first wing plate disposed between thefirst extension part and the first inclined surface of the top surfaceof the first support and rotatably connected to a portion of the firstsupport, wherein the portion of the first support overlaps a boundarybetween the first non-folding area and the first extension part in aplan view; and a second wing plate disposed between the second extensionpart and the second inclined surface of the top surface of the secondsupport and rotatably connected to a portion of the second support,wherein the portion of the second support overlaps a boundary betweenthe second non-folding area and the second extension part in a planview, wherein the first wing plate and the second wing plate rotate withrespect to a first rotation shaft and a second rotation shaft extendingin the second direction.
 13. The display device of claim 12, wherein thesecond wing plate is symmetric to the first wing plate, the secondinclined surface of the top surface of the second support is symmetricto the first inclined surface of the top surface of the first support, adistance between the first wing plate and the first inclined surface ofthe top surface of the first support increases in a direction toward thecurved part when the display module is unfolded, and the first inclinedsurface of the top surface of the first support forms an angle in arange of about 6.5° to about 12.5° with the first wing plate when thedisplay module is unfolded.
 14. The display device of claim 12, whereinthe first wing plate contacts the first inclined surface of the topsurface of the first support, and the second wing plate contacts thesecond inclined surface of the top surface of the second support upon astress of the folding area when the display module is folded.
 15. Thedisplay device of claim 12, wherein the hinge comprises: a cover partdisposed between the first support and the second support and below thefirst wing plate and the second wing plate; a first rotation unit and asecond rotation unit connected to opposite ends of the cover part in thesecond direction; and a plurality of hinge parts connected to oppositesides of the first support and the second support in the seconddirection, and the first rotation unit and the second rotation unit,wherein the cover part includes a groove facing the curved part andextending in the second direction, and the biaxial rotation shaftoverlaps the curved part and the groove in a plan view.
 16. The displaydevice of claim 15, a side of the first wing plate and a side of thesecond wing plate facing each other, and a central portion of the curvedpart are disposed in the groove when the display module is folded. 17.The display device of claim 1, wherein the first non-folding area facesthe second non-folding area when the display module is in-folded.
 18. Adisplay device comprising: a display module comprising a firstnon-folding area, a second non-folding area, and a folding area disposedbetween the first non-folding area and the second non-folding area, thefirst non-folding area, the second non-folding area, and the foldingarea being arranged in a first direction; a first support disposed belowthe first non-folding area; and a second support disposed below thesecond non-folding area, wherein the display module is folded byrotation of the first support and the second support with respect tobiaxial rotation shafts disposed below the folding area, wherein thefolding area comprises: a curved part bent to have a predeterminedcurvature radius when the display module is folded; a first extensionpart disposed between the first non-folding area and the curved part;and a second extension part disposed between the second non-folding areaand the curved part, wherein the folding area has a length in a range of35 mm to 45 mm in the first direction when the display module isunfolded, and wherein the first extension part forms an angle in a rangeof 6.5° to 12.5° with a first reference line extending from the firstnon-folding area to the curved part in a same direction as an extensiondirection of the non-folding area when the display module is folded. 19.The display device of claim 18, wherein the curved part of the foldingarea is bent to have a predetermined curvature radius in a range ofabout 1.5 mm to about 5.0 mm.